Table 2.
A comparison of three protein quantification techniques; micro BCA, RP-HPLC, and HPLC-ELSD. For all three methods, the accuracy was determined at three concentrations, while Intra-day and Inter-day precision was calculated across three different concentrations with %RSD shown. The LOD and LOQ were also determined for the respective quantification techniques. Results represent the average of at least three replicate measurements ± standard deviation (SD).
| Concentration | R 2 | Equation | Mean (SD) | %RSD | Accuracy | LOD | LOQ | ||
|---|---|---|---|---|---|---|---|---|---|
| (µg/mL) | Intra-Day | Inter-Day | Intra-Day | Inter-Day | (%) | (µg/mL) | (µg/mL) | ||
| micro BCA | |||||||||
| 5 | 0.9985 | y = 0.013x + 0.0178 | 4.89 (0.75) | 4.48 (0.73) | 4.40 | 2.26 | 95.32 ± 0.94 | 1.85 | 5.61 |
| 20 | 20.86 (1.84) | 20.61 (1.46) | 2.42 | 1.18 | 102.94 ± 1.85 | ||||
| 35 | 35.5 (0.79) | 35.1 (0.79) | 1.76 | 0.38 | 100.63 ± 0.99 | ||||
| RP-HPLC | |||||||||
| 25 | 0.9925 | y = 0.3658x + 0.2811 | 26.02 (1.82) | 27.87 (1.26) | 6.41 | 4.35 | 101.39 ± 0.10 | 2.43 | 7.37 |
| 200 | 193.15 (18.22) | 185.25 (4.24) | 9.32 | 2.28 | 94.53 ± 6.03 | ||||
| 400 | 436.44 (9.08) | 415.40 (5.00) | 2.07 | 1.20 | 102.74 ± 3.45 | ||||
| HPLC-ELSD | |||||||||
| 100 | 0.9946 | y = 75,410x −2 × 106 | 81.17 (3.33) | 87.18 (6.93) | 5.89 | 11.44 | 93.37 ± 4.41 | 0.77 | 2.33 |
| 200 | 203.32 (5.53) | 215.08 (7.90) | 3.09 | 4.19 | 102.31 ± 13.8 | ||||
| 400 | 417.02 (5.57) | 402.31 (36.95) | 1.42 | 9.84 | 99.21 ± 5.59 | ||||